A conventional expandable luggage 10 is shown in FIGS. 1 and 2 comprising a main body 11 supported by a main frame 14, a frame element 15, an expandable pouch 13 coupled between main body 11 and frame element 15, and a door panel 12 coupled to frame element 15 by a zipper. A zipper 131 is provided on expandable pouch 13 wherein the expandable pouch 13 is expanded to its maximum when zipper 131 is open and the expandable pouch 13 is retracted to its minimum when zipper 131 is closed. However, the previous design suffered from several disadvantages. In detail, the expanded expandable pouch 13 is not supported by any mechanism. As such, the bottom 132 of expandable pouch 13 may be bulged downwardly due to the weight of items packed in the luggage 10 (FIG. 2). This may obstruct the smoothness when towing the luggage, or in an extreme case cause the damage of luggage 10. Further, luggage 10 tends to deform after a plurality of times of use due to the bulged bottom 132 of expandable pouch 13. Furthermore, luggage 10 may not stand upright easily due to the bulged bottom 132 of expandable pouch 13.